package java_collection.set;

import java.util.Set;
import java.util.TreeSet;


public class TreeSetTest {

	public static void main(String[] args) {
		
		Set<Integer> s = new TreeSet<>();
		s.add(10); // ok
		s.add(null); // NullPointerException
		
		System.out.println(s);

	}

}
